Cable television is a system of providing television to consumers via radio frequency signals. These signals are transmitted to televisions (TVs) through fixed optical fibers or coaxial cables as opposed to an over-the-air method used in traditional television broadcasting (via radio waves) in which a television antenna is used. Frequency modulation (FM) radio programming, high-speed Internet, telephony, and similar non-television services may also be provided.
The abbreviation “CATV” is often used to mean “Cable TV”. It originally stood for “community antenna television,” from cable television's origins. For example, in areas where over-the-air reception was limited by mountainous terrain, large “community antennas” were constructed, and cable was run from them to individual homes. Conventional CATV involves distributing a number of television channels collected at a central location (called a head-end) to subscribers (e.g. customers) within a community by a branched network of optical fibers and/or coaxial cables and broadband amplifiers. Since the early 1990s, the most common architecture is the hybrid fiber-coaxial network. As in the case of radio broadcasting, using different frequencies allows many channels to be distributed through the same cable without separate wires for each channel. A set-top box may select one channel from this cable.